N8n:protect Endpoints Agent Skill

Protect REST endpoints with RBAC

Rule: every authenticated route on a @RestController MUST carry an access-scope decorator. If you add a route without one, the IDOR/permission bypass is on you.

Decision

URL has :projectId  → @ProjectScope('<resource>:<op>')
URL has no project  → @GlobalScope('<resource>:<op>')
skipAuth: true      → no decorator + comment explaining alternate auth

@ProjectScope succeeds if the user has the scope globally OR in the project named in the URL. @GlobalScope ignores project relations entirely.

Both decorators come from @n8n/decorators. The middleware lives in packages/cli/src/controller.registry.ts (createScopedMiddleware) and resolves access via userHasScopes in packages/cli/src/permissions.ee/check-access.ts.

Apply the decorator

import { Get, Post, ProjectScope, RestController } from '@n8n/decorators';

@RestController('/projects/:projectId/widgets')
export class WidgetsController {
  @Post('/')
  @ProjectScope('widget:create')          // create
  async create(...) { ... }

  @Get('/:widgetId')
  @ProjectScope('widget:read')            // read one
  async get(...) { ... }

  @Get('/')
  @ProjectScope('widget:list')            // list
  async list(...) { ... }

  @Patch('/:widgetId')
  @ProjectScope('widget:update')          // update
  async update(...) { ... }

  @Delete('/:widgetId')
  @ProjectScope('widget:delete')          // delete
  async delete(...) { ... }
}

Conventions:

• One decorator per route, placed directly under the HTTP-method decorator.
• Use the most specific scope that fits. Reuse *:update for state-changing actions like publish/unpublish/build unless the resource needs to gate them separately (see workflow:publish for the precedent).
• Routes without :projectId and not global-only operations are usually a design smell — flag it.

When the scope doesn't exist yet

Add the resource and ops in packages/@n8n/permissions/:

• src/constants.ee.ts — add to RESOURCES (alphabetical):

   widget: [...DEFAULT_OPERATIONS, 'execute'] as const,

The Scope union (<resource>:<op> template-literal type) auto-derives.

• src/scope-information.ts — add a display name + description per scope.
• src/roles/scopes/project-scopes.ee.ts — add to project roles. Match the workflow precedent unless product says otherwise:
• REGULAR_PROJECT_ADMIN_SCOPES, PERSONAL_PROJECT_OWNER_SCOPES, PROJECT_EDITOR_SCOPES → all CRUDL+execute scopes.
• PROJECT_VIEWER_SCOPES → read/list/execute only.
• PROJECT_CHAT_USER_SCOPES → execute only (if applicable).
• src/roles/scopes/global-scopes.ee.ts — add to GLOBAL_OWNER_SCOPES (admin inherits via concat()). Do not add to member/chat-user globals — they get scopes via project relations.
• Personal-space publishing: if you add a <resource>:publish scope, also append it to PERSONAL_SPACE_PUBLISHING_SETTING.scopes in constants.ee.ts so personal-owner gating matches workflow:publish.
• src/roles/custom-role-scopes.ee.ts — add the resource to PROJECT_CUSTOM_ROLE_OPERATIONS with the ops to render in the permissions matrix, in display order. The editor's SCOPES/SCOPE_TYPES and the save-time whitelist PROJECT_CUSTOM_ROLE_SCOPES both derive from it: a resource missing here cannot reach the UI, and a scope missing from it is rejected on save.
• Frontend wiring — three files; skipping any of them means the new scopes will not appear in the project-role configuration UI:
• packages/frontend/@n8n/stores/src/rbac.store.ts — add <resource>: {} to scopesByResourceId (typecheck will fail otherwise).
• packages/frontend/editor-ui/src/features/roles/project/projectRoleScopes.ts — add the resource to SCOPE_TYPES (the order the resource group appears on the page).
• packages/frontend/@n8n/i18n/src/locales/en.json — add projectRoles.<resource>:<op> (column label) and projectRoles.<resource>:<op>.tooltip (hover description) for every op, plus projectRoles.type.<resource> (the group header).
• Snapshot — update packages/@n8n/permissions/src/__tests__/__snapshots__/scope-information.test.ts.snap to include the new <resource>:* entries.

No DB migration needed — AuthRolesService.init() syncs scopes/roles on every startup. Custom team roles created in the UI are not auto-updated; mention this in the PR description.

Public / unauthenticated routes

{ skipAuth: true } skips the auth middleware → req.user is undefined → adding @ProjectScope would 401 every call. Public routes (third-party webhooks, signed callbacks) must:

• Omit the scope decorator.
• Authenticate via signature/HMAC verification inside the handler (or another route-specific mechanism).
• Carry a comment explaining why no scope is applied, so the next reviewer doesn't try to "fix" it.

Example:

// Third-party webhook callback: do not add @ProjectScope. Auth happens
// via per-platform signature verification inside webhookHandler, and
// :projectId is unused in the (agentId, platform) lookup.
@Post('/:agentId/webhooks/:platform', { skipAuth: true, allowBots: true })
async handleWebhook(...) { ... }

Verify with a route-metadata test

Add a regression test that fails when a future route is added without a scope. Iterate every route on the controller via ControllerRegistryMetadata and assert the gate.

import { ControllerRegistryMetadata } from '@n8n/decorators';
import { Container } from '@n8n/di';
import { WidgetsController } from '../widgets.controller';

const UNAUTHENTICATED_HANDLERS = new Set<string>(); // add public handler names here

const metadata = Container.get(ControllerRegistryMetadata).getControllerMetadata(
  WidgetsController as never,
);
const routeCases = Array.from(metadata.routes.entries()).map(([handlerName, route]) => ({
  handlerName, route,
}));

describe('WidgetsController route access scopes', () => {
  it.each(routeCases)(
    '$handlerName is gated by a project-scoped widget:* check',
    ({ handlerName, route }) => {
      if (UNAUTHENTICATED_HANDLERS.has(handlerName)) {
        expect(route.accessScope).toBeUndefined();
        expect(route.skipAuth).toBe(true);
        return;
      }
      expect(route.accessScope).toBeDefined();
      expect(route.accessScope?.globalOnly).toBe(false);
      expect(route.accessScope?.scope.startsWith('widget:')).toBe(true);
    },
  );
});

Defense in depth (still required)

Decorator alone is not enough when handlers leak data via downstream calls. Service/repository methods should still filter by projectId (or user-scoped helpers like findByUser). The decorator gates *who can call this URL*; the service gates *what they can read*. Both, always.

Reference patterns

• Project-scoped CRUD: packages/cli/src/workflows/workflows.controller.ts, packages/cli/src/credentials/credentials.controller.ts, packages/cli/src/modules/data-table/data-table.controller.ts.
• Mixed global + project: packages/cli/src/controllers/project.controller.ts.